He/she is talking about genetic disorders. Interesting topic. An oncologist is a cancer specialist so I don't know the specific cancer disorder but I'm sure there is one.
Copied, I agree with the person above ^ :’)
The period during which the presence of stromatolites decline is the Proterzoic period. Stromatolites are widely distributed sedimentary structures consisting of laminated carbonate or silicate rocks, produced over geologic time by the trapping, binding, or the precipitating of sediment by groups of microorganisms, primarily cyanobacteria.
